Flow regulating valves are integral components to providing a constant flow rate of fluid as requested by an external command to a combustion chamber, regardless of the inlet flow at the flow regulating valve. Historically, flow regulating valves have been damped with either a laminar leak path or via orifices in non-flowing sense lines.
Laminar leak path damping can provide linear damping over the full range of valve velocities. However the damping is proportional to the kinematic viscosity of the fluid being regulated, therefore the damping is sensitive to temperature variations of the fluid media.
Non-flowing orifice damping exhibits less temperature sensitivity than valves using laminar leak path damping. However, non-flowing orifice damping is proportional to the square of valve velocity. As a result, the orifice provides no damping when the valve is stationary (e.g., valve velocity equal to zero), but can over-damp the valve during large disturbances.